IQQ NOETH-WEST AFRICA. of its arcades rising to over 80 feet in height ; but almost everywhere the ruins of the aqueduct present little more than short detached fragments, utilised as quarries by the local builders, and stripped of their angular stone facing. The very engineers who repaired the aqueduct have destroyed the finest fragment that still remained of the monument raised by Adrian and Septimius Severus: they have pulled down the bridge over the Wed Melian to form the foundations of their modern aqueduct, which it would have been easy to have carried in another direction without increase of expenditure. The remains of the aqueduct, as well as those of the ancient Roman city of Fdna {Udina), have been used to build the walls of farms, the huts, and now abandoned palaces of Mohammedia. Huge megaliths are scattered around the ruins of Udina, and the cisterns have been converted into dwellings and refuges for cattle. The mean discharge of the springs still utilised was in 1885, 175,000 cubic feet dailv, and this quantity will soon be increased one-half by enlarging the area of 8uj)ply. When these works are completed it is expected that the greatest daily discharge will be 425,000 cubic feet, the mean ranging from 250,000 to 275,000 cubic feet. Tunis. Tunis, capital of the Regency and one of the largest cities of the continent, was second to Cairo alone in population at the beginning of this century. Now, however, it is surpassed by Alexandria, and probably by Algiers, if the total lx)pulation within and without the ramparts be taken into consideration. Although more advantageously situated in many respects than the capital of Algeria, it has been, if not outstripped, at least equalled, in consequence of the political, military, administrative, and economical centralisation which more than half a century of French occupation has effected in the town of Algiers. Viewed from a general geographical standpoint, Tunis still possesses a few of those great advantages which Carthage enjoyed ; it is situated near the projecting angle of the Maghreb, between the two basins of the Mediterranean, and lies also near the mouth of the great valley of the river Mejerda, which with its numerous ramifications penetrates into the heart of the Mauritanian mountains and plateaux. Moreover, it has a very healthy climate, thanks to the free circulation of the north winds. Some three thousand years ago, or even at the possibly still more remote period of its founda- tion, certain local features in the relief of the land, offering commercial advantages and facilitating its defence against attack, must necessarily have had a decided influence in the choice of this site for a new Pha'nician settlement. At this point a chain of low limestone hills cuts off the great plain facing westwards in the direction of the Mejerda ; and this strategical position is all the stronger, that both sides of the rocky ridge are enclosed by vast lacustrine depressions. These are the Sebkha-el-St>ljum to the south-west, which. increases and decreases with the rainy and dry st^asons, and the IJahira, or " Little Sea," to the north-east, whose level never changes, thanks to the " channel " connecting this lagoon with the Mediter-
